By Dr Shireen Kassam
There is an open question as to whether those following 100% plant-based diets should take a long chain omega-3 supplement. There are 3 main omega-3 fatty acids. The short chain omega-3 fatty acid alpha linolenic acid (ALA) and the two long chain omega 3 fatty acids — DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). ALA is considered essential and must be obtained from the diet. ALA can be found in plants. DHA and EPA in most diet patterns is usually obtained from fish, although fish obtain it from marine algae. The body can convert ALA to DHA/EPA but the rate of conversion varies and may reduce with age and can differ between individuals based on gender, genetic factors and the overall composition of the diet. To meet daily requirements of 2–4 grams of ALA per day requires a tablespoon of chia seeds or ground flaxseeds (linseeds), two tablespoons of hemp seeds or six walnut halves.
There is evidence to suggest that if DHA and EPA are not being obtained from the diet, there is an increase in the efficiency of conversion from ALA. In the EPIC study, DHA/EPA levels in the blood did not differ as much as expected, although were definitely lower, when comparing fish eaters, vegetarians and vegans confirming that those on a vegan diet do make some EPA/DHA. Studies also show that vegans have higher levels of ALA than omnivores.
There is uncertainty as to whether there is benefit in taking DHA/EPA directly so as not to rely on conversion from ALA. This may be particularly important for brain health as you get older. The most reliable source in a WFPB diet would be a microalgae supplement and the dosage for adults is 250mg DHA/EPA combination per day. Supplementation is recommended during pregnancy and breast feeding at higher doses (400–500mg). To boost your conversion of ALA to DHA & EPA it is also important to maintain an optimal ratio of omega-6 to omega-3 fatty acids, around of 4:1. Omega-6 fats are also essential but are found in abundance in a plant-based diet from seeds, nuts and plant-based oils, such as sunflower, safflower, soybean or corn oil. The modern Western diet is often too high in omega-6 because of the abundant consumption of processed foods and oils. Thus, limiting omega-6 rich oil consumption will help the conversion of ALA to DHA/EPA.
Many plant-based physicians have been recommending a DHA/EPA supplement for all those following a whole food plant-based diet. However, Dr Michael Klaper has recently posted a video on why he is stopping his DHA supplement. His main reason being the potential link between high blood levels of DHA and aggressive prostate cancer in men. However, the data are not black and white and there has never been a study examining the effects of omega-3 supplementation in vegans. Other large studies examining high dose omega-3 supplementation have not shown an increased risk of cancer. I am not sure we know the definite answer to this question but it is worth keeping up with the science and having an open mind. Until then we will have to make decisions on an individual basis.